The present invention relates to an optical system usable, for example, as an ocular optical system for a head-mounted image display apparatus or a projection optical system for a color film projection apparatus.
To display or project a color image free from uneven color by using a plurality of illuminating light sources, e.g. R (red), G (green) and B (blue), it has heretofore been necessary to combine together light from each light source provided individually by using a plurality of color filters or dichroic mirrors, resulting in a large-sized and heavy-weight arrangement undesirably. Therefore, such an arrangement is not suitable for a head-mounted image display apparatus, for example. Furthermore, because color filters and dichroic mirrors are costly, it is impossible to supply a head-mounted image display apparatus or the like at low cost.